Expendable beam transmissometer
US7068362B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 2003 |
| Grant date | Jun 27, 2006 |
| Priority date | — |
| Expiry date | Sep 11, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J1/42
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention provides apparatus for a beam transmissometer. In an embodiment, the beam transmissometer includes a LED signal source, collimating apparatus, a retroreflector that directs the projected beam, imaging apparatus that directs the beam onto a detector that converts the projected beam into an electrical signal, and signal processing circuitry that enhances the reception of the optical beam. The LED signal source is modulated in a pulsed fashion so that the effects of beam reflection are ameliorated. Signal processing circuitry amplifies, filters, and synchronizes to the electrical signal. A calculating unit uses the processed signal to determine a beam attenuation coefficient, which is indicative of the visibility of a medium in which the transmissometer is immersed. A method is also provided for aligning optics of a beam transmissometer. The method determines an offset and a rotation of a retroreflector housing that causes an optical beam to be centered.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.